I am going to the hardware store to buy blank keys and a file for the thing where you stick the blank in and file it down. What type of file should i get and what is this "key making" technique called?
A small pippin file works best. If that is not available, get the smallest triangle file you can.
Just remember, don't let your cuts get too deep, with sharp corners. The sharp corners will bind your key against a pin, and you won't be able to remove the key from the lock.